The number and proportion of substance abusing women in prison are increasing, creating a need for programs tailored to this population, and for evaluation of such programs. The specific aims of this project are: 1) to conduct a rigorous evaluation of the effectiveness of prison TC treatment for substance abusing women offenders; 2) to investigate the treatment process for the target population and to explore the relationship between the process and outcome of treatment; 3) to evaluate the cost and cost effectiveness of treatment; and 4) to assess issues in obtaining and making use of aftercare services and provide information regarding the additional contribution of aftercare treatment. The core investigation randomly assigns female substance abusing offenders, over four years (n=1000), at the Denver Women's Correctional Facility to either a TC program, Recovery By Choice, the experimental (E) condition (n=500), or to a non-TC standard program, the comparison (C) condition (n=500). The study predicts better outcomes for the TC group in an intent- to-treat analysis of all study entrants. The Aim 4 supplementary study of aftercare, with no random assignment, follows program completers from E and C as they enter mandatory aftercare, choosing either TC aftercare or a non-TC treatment alternative. The research employs a prospective, longitudinal, repeated measures assessment with five points (baseline, 6-, 12-, 18-, and 24-months post-baseline) and employs standard outcome measures (e.g., drug use, crime, and employment), and specific measures of particular concern to female offenders (e.g., self-esteem, trauma and abuse, and parenting practices). In addition to self-report data, urine toxicology and criminal record data are obtained. The study collects process data, guided by the Texas Christian University Treatment Process Model, and cost data using a specially designed cost analysis instrument. The project contributes to a theoretical advance in our understanding of the process of treatment for women offenders in prison TCs. It advances research through a rigorous study of TC prison program effectiveness for women compared to another, routine treatment. It guides practice by delineating treatment elements for women and by examining the effectiveness of a TC program that organizes these elements. Finally, it integrates outcome and economic analysis to inform policy and planning about the effectiveness and cost-effectiveness of the TC treatment under study. Perhaps most significantly, it tests TC principles and methods found effective with substance-abusing male offenders that are adapted for women, thereby increasing the potential utility of these strategies.